Update version of giter8 plugin 0.3.{1 --> 2}

Fixed the following error in my environment:

```
[warn]  ::::::::::::::::::::::::::::::::::::::::::::::
[warn]  ::          UNRESOLVED DEPENDENCIES         ::
[warn]  ::::::::::::::::::::::::::::::::::::::::::::::
[warn]  :: net.databinder#giter8-plugin;0.3.2: not found
[warn]  ::::::::::::::::::::::::::::::::::::::::::::::
[warn]
[warn]  Note: Some unresolved dependencies have extra attributes.  Check that these dependencies exist with the requested attributes.
[warn]          net.databinder:giter8-plugin:0.3.2 (sbtVersion=0.11.3, scalaVersion=2.9.1)
```